The invention relates to a vehicle door, especially a motor vehicle door. Typically, such a door basically comprises a structure having an outer wall and an inner wall in which at least one opening is provided, and a covering.
The object of the invention is, in particular, to provide an air-tight and moisture-tight door which has a reduced weight, good acoustic insulation and a large capacity to absorb energy in the case of impact, and which is readily recyclable, easy to assemble and inexpensive.
DE-A-43 37 468 describes a door whose covering has a panel which is attached to the structure and which provides sealing relative to the inner wall. The covering also comprises a frame surrounding the panel in order to hold it in position relative to the inner wall. The frame is fixed to the inner wall of the structure by fixing means extending through the panel.
However, that form of door is not entirely satisfactory because its air-tightness and moisture-tightness, and also its sound-proofing have weaknesses, in particular at the site of the means for fixing the frame to the inner wall. Thus it very often proves necessary to carry out finishing operations in order to adhere to the manufacturer""s specifications. Those finishing operations, which consist, in particular, in fitting foam members around the fixing means, increase the cost of the door and do not enable an entirely satisfactory quality to be achieved.
In order to overcome those various disadvantages, the invention proposes that the panel be self-supporting, that the door comprise fixing means having a first part attached to the structure and a second part attached to the panel, the first part and the second part cooperating with one another in order to fix the panel directly to the structure, and that the frame be supported by the panel.
Thus, holes permitting the passage of elements extending through the thickness of the panel and in effect reducing the efficiency of the panel are dispensed with. Furthermore, the assembly of the door is facilitated.
The invention also proposes that the panel be made of expanded plastics material.
Thus, the panel has a low weight, good acoustic insulation and a high degree of safety in the case of impact.
Another advantageous feature enabling the sound-proofing capacity of the door and its air-tightness and moisture-tightness to be improved consists in that the panel comprises a first water-tight layer and a second layer having better acoustic insulation than the first, both the first layer and the second layer being made of expanded plastics material.
The fact that the panel is produced in several layers having different sound-proofing and air- and water-tightness capacities enables the overall sound-proofing capacity of the panel to be improved while maintaining good air-tightness and water-tightness.
Another feature of the invention which is aimed at improving energy absorption by the door in the case of impact, while maintaining satisfactory sound-proofing and reducing the weight, the cost and the thickness of the door, consists in that the panel has (a) zone(s) of high density for absorbing impact against a passenger of the vehicle and (a) zone(s) of lower density for reducing the weight of the door.
In the case of impact, especially side impact, there is a risk that the door will come into contact with the occupants of the vehicle in localised zones, particularly opposite the occupants"" hips. The high density of the expanded material in those zones enables the function of energy absorption to be integrated in the panel.
The invention also proposes that the panel comprise members made of expanded polypropylene and that it be at least partially covered with a decorative layer, the polypropylene members being welded (agglomerated) to one another and to the decorative layer.
Thus, the production of the panel and its connection to the decorative layer can be achieved simultaneously by melting the polypropylene.
One feature of the invention consists in that the panel comprises members made of expanded polypropylene and is at least partially covered with a sheet defining a grained solid surface obtained by melting the surface of the expanded polypropylene members.
The panel can thus be easily decorated at low cost.
In order to improve the insulation and sound absorption of the door, the invention proposes that the covering comprise at least one closed cavity.
The fact that air is trapped in the covering reduces the propagation of noise through the covering and improves the absorption thereof. In addition, the presence of that (those) cavity (cavities) reduces the weight of the covering.
Advantageously, the cavity defines an air layer between the panel and the frame.
It is therefore easy to create a double-wall phenomenon with air trapped inbetween, by providing a space between the frame and the panel, with the exception of over the entire periphery of the frame.
In order further to improve air-tightness and moisture-tightness, and also the sound-proofing capacity of the door, the invention proposes that the panel incorporate sealing means which extend along the entire periphery of the panel and which are disposed in contact with the inner wall.
That simple solution, which is inexpensive and does not complicate the assembly of the door, notably reduces leakage between the panel and the inner wall because the sealing means completely surround the opening.
Advantageously, the sealing means comprise a relatively rigid rib and a relatively flexible lip.
The rib, which is more rigid than the lip, provides for most of the sealing. The lip, because it is more flexible, completes the sealing action without complicating the assembly of the door, inasmuch as it provides only moderate resistance.
According to another advantageous feature of the invention also aimed at improving the sound-proofing capacity of the door and its air-tightness and moisture-tightness, the invention proposes that:
the panel have receptacles that are adapted to receive functional elements by surrounding them,
channels be integrated in the panel, the channels being adapted to receive electrical wires that are adapted to be connected to the functional elements,
the passage of the electrical wires through the panel be centralised, so that the holes extending through the panel are limited to a centralised passage for the electrical wires, a passage for the means controlling the opening of the door from inside the vehicle, possibly a passage for holding the door-operating handle on the structure and possibly a passage opposite a loudspeaker.
In particular, this solution overcomes the weaknesses of the prior art that are attributable to the passages provided in the panel for receiving the functional elements. The number of passages through the panel is reduced, which increases its efficiency from the point of view of sound-proofing and water-tightness and air-tightness. Some passages could possibly be common passages. The term xe2x80x9cpossiblyxe2x80x9d means that, in some cases, those passages could be dispensed with.
The invention also proposes that channels be integrated in the panel, the channels being adapted to receive wires or cables, and having, in succession, a substantially U-shaped section and a substantially xcexa9-shaped section.
The xcexa9-shaped channel portions define clips integrated in the panel in order to hold the wires or cables in the channels, while the U-shaped portions enable the wires to be inserted more easily into the channels.
In order further to improve the properties of the panel, the invention proposes that the panel have a portion which is inserted in the said opening. This solution does not increase the space requirement of the door because the said portion of the panel occupies a zone which was previously substantially empty.
In order to fix the panel to the structure, the invention proposes that, advantageously, the fixing means comprise units including a clip attached to a clip-holder welded to the panel, and a hole provided in the inner wall, the clip being inserted through said hole.